CN118085850A - Temperature ratio fluorescent probe based on triplet state-triplet state annihilation up-conversion luminescence and preparation method and application thereof - Google Patents

Abstract

The invention discloses a temperature ratio fluorescent probe based on triplet-triplet annihilation up-conversion luminescence, and a preparation method and application thereof. The temperature ratio fluorescent probe comprises thermally-activated up-conversion crystallites and non-thermally-activated up-conversion crystallites; the thermally-activated up-conversion crystallites comprise a first photosensitizer and a first triplet annihilator, and the non-thermally-activated up-conversion crystallites comprise a second photosensitizer and a second triplet annihilator; wherein the excitation wavelength of the first photosensitizer is the same as that of the second photosensitizer, and the first photosensitizer and the second photosensitizer are selected from metal complexes absorbed in a near infrared region of 600-1000 nm. By utilizing the characteristics of different luminescent colors and opposite response of luminescent intensity to temperature change of the two upconversion microcrystals, the obtained temperature ratio fluorescent probe has the characteristics of higher relative sensitivity, wide temperature test range, visual temperature change and the like, can realize non-contact temperature detection under near infrared light irradiation, and has wide application prospect in the field of temperature sensing.

Description

A temperature ratio fluorescence probe based on triplet-triplet annihilation upconversion luminescence and its preparation method and application

Technical Field

The present invention relates to the technical field of organic luminescent materials, and more specifically to a temperature ratio fluorescent probe based on triplet-triplet annihilation upconversion luminescence, and a preparation method and application thereof.

Background technique

With the development of science and technology, the measurement accuracy requirements for many physical quantities are getting higher and higher. Among them, temperature is one of the frequently used physical quantities. In electronic devices, aerospace, environmental monitoring, scientific research and industrial production, higher requirements are put forward for the accurate measurement of temperature. However, many traditional contact thermometers, such as thermal expansion thermometers, pressure thermometers, thermocouple thermometers, and resistance thermometers cannot meet the needs of these practical applications. Fluorescence temperature probes can achieve indirect measurement of temperature based on the change of fluorescence intensity caused by the change of molecular transition rate with temperature. However, in practical applications, the single excited state fluorescence temperature sensing system will be affected by the uneven distribution of probe molecules and changes in molecular concentration, which can easily cause measurement errors. The ratiometric fluorescence probe system has self-calibration and can avoid errors caused by factors such as uneven molecular distribution. Ratiometric fluorescence probes have gradually become the object of extensive attention of researchers due to their advantages such as high resolution and sensitivity and short response time.

The construction of temperature ratio fluorescent probes is mostly based on the differential response of fluorescence intensity at two locations with different wavelengths to temperature. The two luminescences can come from different luminescent species or from different excited states of the same compound, and the fluorescence intensities at the two locations respond to temperature differently: for example, the fluorescence at one wavelength changes significantly with temperature, while the fluorescence at the other wavelength has no response or weak response to temperature; or the response trends of the fluorescence intensities at the two wavelengths to temperature are opposite, which is more conducive to improving sensitivity.

Near-infrared light has low energy, strong penetration, and little damage to materials, but it cannot be visualized. Upconversion luminescent materials can convert low-energy near-infrared light into high-energy visible light, achieving long-distance, deep-level visualization detection. At the same time, near-infrared light has relatively weak background light, which can effectively reduce the influence of stray light generated by the pump light source on the signal light, thereby improving the measurement accuracy. Although temperature probes based on traditional inorganic rare earth upconversion nanoparticles have been developed, some of them rely on single-emission fluorescence and are greatly affected by the environment, and some double-emission fluorescence relies on the precise tuning of the concentrations of two luminescent units, which is not conducive to practical application. Triplet-triplet annihilation upconversion (TTA-UC) materials have the characteristics of low excitation power, high upconversion efficiency, and different upconversion systems with different temperature sensitivities. They have the conditions for preparing temperature ratio fluorescence probes, but currently due to the small number of selectable near-infrared absorption photosensitizers, the sensitivity of temperature ratio fluorescence probes is low, the detection temperature range is limited, and temperature visualization cannot be achieved. For example, in 2021, Song Yanlin's research group has tried to encapsulate the TTA-UC system in micelles, and use the upconversion luminescence and downconversion luminescence of a single upconversion system to form a ratiometric fluorescent probe, but its temperature detection range is narrow, only 30-60°C, and the excitation light is 532nm, which cannot be visualized, severely limiting its practical application. Therefore, it is urgent to develop more TTA-UC upconversion materials with near-infrared absorbing metal complexes as photosensitizers to expand the temperature ratio fluorescence type, which will help to perform non-contact temperature measurement at deeper depths of objects and achieve temperature visualization.

Summary of the invention

To solve the above problems, the first object of the present invention is to provide a temperature ratio fluorescent probe based on triplet-triplet annihilation upconversion luminescence. The temperature ratio fluorescent probe comprises two different upconversion materials, namely, thermally activated upconversion microcrystals and non-thermally activated upconversion microcrystals. By utilizing the characteristics that the luminescence colors of the two upconversion microcrystals are different and the luminescence intensity has opposite responses to temperature changes, high-sensitivity and visual applications in the field of temperature sensing can be achieved.

The second object of the present invention is to provide a method for preparing the temperature ratio fluorescent probe as described above.

The third object of the present invention is to provide an application of the temperature ratio fluorescent probe as described above in the field of temperature sensing.

In order to achieve the above first object, the present invention adopts the following technical scheme:

The present invention discloses a temperature ratio fluorescent probe based on triplet-triplet annihilation upconversion luminescence, wherein the temperature ratio fluorescent probe comprises a thermally activated upconversion microcrystal and a non-thermally activated upconversion microcrystal; the thermally activated upconversion microcrystal comprises a first photosensitizer and a first triplet annihilation agent, and the non-thermally activated upconversion microcrystal comprises a second photosensitizer and a second triplet annihilation agent;

Wherein, the first photosensitizer and the second photosensitizer have the same excitation wavelength and are selected from metal complexes absorbing in the near-infrared region of 600-1000nm.

In the present invention, thermally activated upconversion microcrystals and non-thermally activated upconversion microcrystals are used to form the core components of the temperature ratio fluorescent probe, wherein the luminescence intensity of the thermally activated upconversion microcrystals gradually increases with increasing temperature, and the luminescence intensity of the non-thermally activated upconversion microcrystals gradually decreases with increasing temperature, and the two upconversion microcrystals meet the basic requirements of being used as a temperature ratio fluorescent probe after being used in combination. By changing the blending ratio of thermally activated upconversion microcrystals and non-thermally activated upconversion microcrystals, the luminescence intensity of different upconversion materials can be adjusted, and by changing the types of photosensitizers and annihilators in each upconversion material, the position of the maximum luminescence peak wavelength of different upconversion materials can be adjusted. When a near-infrared absorbing metal complex is selected as a photosensitizer to prepare two upconversion microcrystals, the obtained temperature ratio fluorescent probe can realize non-contact temperature detection under near-infrared light irradiation, and can effectively reduce the influence of stray light generated by the pump light source on the signal light, thereby improving the measurement accuracy.

The temperature ratio fluorescent probe provided by the present invention has a wide temperature test range and low-temperature test capability, and can realize visual testing of temperature changes in the range of 223K-300K (i.e., -50°C~27°C), and the relative sensitivity can reach up to 4.5%/K.

Further, the first photosensitizer and the second photosensitizer may be the same or different. Based on the premise of the same excitation wavelength, they can be selected from any one of a tetraphenyl tetrabenzoporphyrin metal complex of palladium or platinum, a rare earth complex with a photosensitive core of ytterbium, a rare earth complex with a photosensitive core of neodymium, and a rare earth complex with a photosensitive core of thulium. The aforementioned sameness can be understood as the first photosensitizer and the second photosensitizer are selected from exactly the same photosensitizer, and the aforementioned difference can be understood as the first photosensitizer and the second photosensitizer are both selected from rare earth complexes, for example, a rare earth complex with a photosensitive core of ytterbium. , any one of the rare earth complexes with neodymium as the photosensitive core and the rare earth complexes with thulium as the photosensitive core, the photosensitizer structure should be the same, and the photosensitizer structure can be different (for example, mononuclear ytterbium complexes, polynuclear ytterbium complexes, etc.). It can also be understood that the first photosensitizer and the second photosensitizer are both selected from conventional photosensitizers such as tetraphenyltetrabenzoporphyrin metal complexes of palladium or platinum, that is, the structures are basically the same, and the main difference lies in the different metal types in the center of the parent core (for example, tetraphenyltetrabenzoporphyrin metal complexes of palladium or tetraphenyltetrabenzoporphyrin metal complexes of platinum).

Furthermore, the first photosensitizer and the second photosensitizer are selected from diketone complexes whose photosensitive core is ytterbium or palladium (II) tetraphenyltetrabenzoporphyrin.

According to the characteristic that the luminescence intensity of the two up-conversion microcrystals has opposite responses to temperature changes, the first triplet annihilator and the second triplet annihilator represent different types of triplet annihilators, and the first triplet annihilator can be selected from one or more of 9,10-diphenylanthracene or its derivatives, 9,10-(diphenylethynyl)anthracene or its derivatives, and 9,10-bis[(triisopropylsilyl)ethynyl]anthracene, and the second triplet annihilator can be selected from one or more of rubrene, perylenetetracarboxamide diimide or their derivatives.

In a specific embodiment, the first photosensitizer and the second photosensitizer are selected from any one of Yb(DBM) ₃ (H ₂ O), Yb ₅ (DBM) ₁₀ (OH) ₅ , and palladium (II) tetraphenyltetrabenzoporphyrin, and the structure thereof is shown below:

Yb(DBM) ₃ (H ₂ O),

Yb ₅ (DBM) ₁₀ (OH) ₅ ,

Palladium(II) tetraphenyltetrabenzoporphyrin (commercially available product).

In one embodiment, the first triplet annihilator is selected from one of the structures shown below:

9,10-Bis[(triisopropylsilyl)ethynyl]anthracene,

9,10-(Diphenylethynyl)anthracene,

Derivatives of 9,10-(diphenylethynyl)anthracene,

9,10-Diphenylanthracene,

One of the derivative structures of 9,10-diphenylanthracene,

The second structure of the derivative of 9,10-diphenylanthracene

The structure of the derivative of 9,10-diphenylanthracene

The fourth structure of the derivative of 9,10-diphenylanthracene;

Here, R is any one of Cl, Br, and I.

In one embodiment, the second triplet annihilator is selected from one of the following structures:

3,4,9,10-Perylenetetracarboxylic acid diimide,

N,N'-di(ethylpropyl)perylene-3,4,9,10-tetracarboxylic acid (PDI),

N,N-dioctyl-3,4,9,10-perylenetetracarboxylic acid diimide (ODI),

Rubrene.

Further, the molar ratio of the first photosensitizer to the first triplet annihilator is 1:1-1:500; illustratively, the molar ratio of the first photosensitizer to the first triplet annihilator can be 1:1, 1:5, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, 1:60, 1:70, 1:80, 1:90, 1:100, 1:200, 1:300, 1:400, 1:500, etc. The molar ratio of the second photosensitizer to the second triplet annihilator is 1:1-1:300; illustratively, the molar ratio of the second photosensitizer to the second triplet annihilator can be 1:1, 1:5, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, 1:60, 1:70, 1:80, 1:90, 1:100, 1:110, 1:120, 1:130, 1:140, 1:150, 1:160, 1:170, 1:180, 1:190, 1:200, 1:300, etc.

Furthermore, in the thermally activated upconversion microcrystals, the first photosensitizer is selected from Yb(DBM) ₃ (H ₂ O), and the first triplet annihilator is selected from 9,10-(diphenylethynyl)anthracene, and in the corresponding non-thermally activated upconversion microcrystals, the second photosensitizer is selected from Yb(DBM) ₃ (H ₂ O), and the second triplet annihilator is selected from N,N'-di(ethylpropyl)perylene-3,4,9,10-tetracarboxylic acid. In a specific embodiment, the molar ratio of the first photosensitizer to the first triplet annihilator is 1:10-1:50, and the molar ratio of the second photosensitizer to the second triplet annihilator is 1:5-1:20.

Furthermore, in the thermally activated upconversion microcrystals, the first photosensitizer is selected from Yb(DBM) ₃ (H ₂ O), and the first triplet annihilator is selected from 9,10-bis[(triisopropylsilyl)ethynyl]anthracene, and in the corresponding non-thermally activated upconversion microcrystals, the second photosensitizer is selected from Yb(DBM) ₃ (H ₂ O), and the second triplet annihilator is selected from N,N'-di(ethylpropyl)perylene-3,4,9,10-tetracarboxylic acid. In a specific embodiment, the molar ratio of the first photosensitizer to the first triplet annihilator is 1:1-1:10, and the molar ratio of the second photosensitizer to the second triplet annihilator is 1:5-1:20.

Furthermore, in the thermally activated upconversion microcrystals, the first photosensitizer is selected from Yb(DBM) ₃ (H ₂ O), and the first triplet annihilator is selected from 9,10-(diphenylethynyl)anthracene, and in the corresponding non-thermally activated upconversion microcrystals, the second photosensitizer is selected from Yb(DBM) ₃ (H ₂ O), and the second triplet annihilator is selected from N,N-di-n-octyl-3,4,9,10-perylenetetracarboxamide diimide. In a specific embodiment, the molar ratio of the first photosensitizer to the first triplet annihilator is 1:10-1:50, and the molar ratio of the second photosensitizer to the second triplet annihilator is 1:5-1:15.

Furthermore, in the thermally activated upconversion microcrystals, the first photosensitizer is selected from Yb(DBM) ₃ (H ₂ O), and the first triplet annihilator is selected from 9,10-bis[(triisopropylsilyl)ethynyl]anthracene, and in the corresponding non-thermally activated upconversion microcrystals, the second photosensitizer is selected from Yb(DBM) ₃ (H ₂ O), and the second triplet annihilator is selected from N,N-di-n-octyl-3,4,9,10-perylenetetracarboxamide diimide. In a specific embodiment, the molar ratio of the first photosensitizer to the first triplet annihilator is 1:1-1:10, and the molar ratio of the second photosensitizer to the second triplet annihilator is 1:5-1:15.

Furthermore, in the thermally activated upconversion microcrystals, the first photosensitizer is selected from Yb(DBM) ₃ (H ₂ O), and the first triplet annihilator is selected from 9,10-bis[(triisopropylsilyl)ethynyl]anthracene, and in the corresponding non-thermally activated upconversion microcrystals, the second photosensitizer is selected from Yb(DBM) ₃ (H ₂ O), and the second triplet annihilator is selected from rubrene. In a specific embodiment, the molar ratio of the first photosensitizer to the first triplet annihilator is 1:1-1:10, and the molar ratio of the second photosensitizer to the second triplet annihilator is 1:10-1:80.

Furthermore, in the thermally activated upconversion microcrystals, the first photosensitizer is selected from Yb ₅ (DBM) ₁₀ (OH) ₅ , and the first triplet annihilator is selected from 9,10-(diphenylethynyl) anthracene, and in the corresponding non-thermally activated upconversion microcrystals, the second photosensitizer is selected from Yb ₅ (DBM) ₁₀ (OH) ₅ , and the second triplet annihilator is selected from N,N'-di(ethylpropyl)perylene-3,4,9,10-tetracarboxylic acid. In a specific embodiment, the molar ratio of the first photosensitizer to the first triplet annihilator is 1:1-1:10, and the molar ratio of the second photosensitizer to the second triplet annihilator is 1:1-1:4.

Furthermore, in the thermally activated upconversion microcrystals, the first photosensitizer is selected from palladium (II) tetraphenyl tetrabenzoporphyrin, and the first triplet annihilation agent is selected from 9,10-diphenylanthracene, and in the corresponding non-thermally activated upconversion microcrystals, the second photosensitizer is selected from palladium (II) tetraphenyl tetrabenzoporphyrin, and the second triplet annihilation agent is selected from rubrene. In a specific embodiment, the molar ratio of the first photosensitizer to the first triplet annihilation agent is 1:100-1:500, and the molar ratio of the second photosensitizer to the second triplet annihilation agent is 1:100-1:300.

Further, the mass ratio of the thermally activated upconversion microcrystals to the non-thermally activated upconversion microcrystals is 1:1-1:1000; preferably, the mass ratio of the thermally activated upconversion microcrystals to the non-thermally activated upconversion microcrystals is 1:1-1:50; illustratively, the mass ratio of the thermally activated upconversion microcrystals to the non-thermally activated upconversion microcrystals can be 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, etc.

In order to achieve the above second purpose, the present invention adopts the following technical solutions:

The present invention discloses a method for preparing the temperature ratio fluorescent probe as described above, comprising the following steps:

The first photosensitizer and the first triplet annihilator are dispersed in an organic solvent, and then added into water to reprecipitate solids, stirred until the mixture is uniform, allowed to stand, centrifuged, and dried to obtain thermally activated upconversion microcrystals;

The second photosensitizer and the second triplet annihilator are dispersed in an organic solvent, and then added into water to reprecipitate solids, stirred until the mixture is uniform, allowed to stand, centrifuged, and dried to obtain non-thermally activated upconversion microcrystals;

The thermally activated upconversion microcrystals and the non-thermally activated upconversion microcrystals are fully mixed in proportion to obtain a temperature ratio fluorescent probe.

Furthermore, the organic solvent is selected from one or more of tetrahydrofuran, chloroform, dimethyl sulfoxide, and N,N-dimethylformamide.

Furthermore, the stirring speed is 1000-2000 r/min, and the stirring time is 0-5 min and does not include 0 min.

Furthermore, the centrifugal speed is 5000-10000 r/min, and the centrifugal time is 5-10 min.

Furthermore, the standing time is 2-8 hours.

Furthermore, the thermally activated upconversion microcrystals and the non-thermally activated upconversion microcrystals are fully mixed by directly mixing the two types of upconversion microcrystals by mechanical shaking, and the mechanical shaking mixing time is not less than 5 minutes.

In order to achieve the third object, the present invention adopts the following technical solutions:

The present invention discloses the application of the temperature ratio fluorescent probe as described above in the field of temperature sensing.

Furthermore, when the first photosensitizer and the second photosensitizer in the thermally activated upconversion microcrystals and the non-thermally activated upconversion microcrystals are selected from tetraphenyltetrabenzoporphyrin metal complexes of palladium or platinum, rare earth complexes with a photosensitive core of ytterbium, rare earth complexes with a photosensitive core of neodymium, and rare earth complexes with a photosensitive core of thulium, since they can absorb excitation light in the near-infrared region of 600-1000nm, the temperature ratio fluorescent probe can be further used in visual non-contact temperature monitoring of the inside of materials or devices by utilizing the high penetrability and low damage of near-infrared light.

The beneficial effects of the present invention are as follows:

1. The temperature ratio fluorescent probe based on triplet-triplet annihilation upconversion luminescence provided by the present invention uses a metal complex absorbing in the near-infrared region of 600-1000nm as a photosensitizer, which broadens the types of temperature ratio fluorescent probes and can realize temperature detection at low temperatures. The detection range is 223K-300K and has a high relative sensitivity.

2. The temperature ratio fluorescent probe based on triplet-triplet annihilation upconversion luminescence provided by the present invention utilizes a near-infrared light-sensitive metal complex photosensitizer to achieve non-contact temperature detection under near-infrared light irradiation. The material makes full use of the high penetrability of near-infrared light, causes little damage to the material, has no background light, and can effectively reduce the influence of stray light generated by the pump light source on the signal light, thereby improving the measurement accuracy.

3. The temperature ratio fluorescent probe based on triplet-triplet annihilation upconversion luminescence provided by the present invention adopts a combination of two upconversion luminescent materials with different temperature sensitivities and doping to achieve the ratio fluorescence change of upconversion luminescence to temperature. Compared with the prior art, it is simple to operate and does not require complicated preparation processes. It can be prepared into various forms of temperature sensors such as solid or liquid according to needs.

4. The temperature ratio fluorescent probe based on triplet-triplet annihilation upconversion luminescence provided by the present invention utilizes rare earth complexes as photosensitizers and organic molecules as receptors. Compared with traditional temperature ratio fluorescent sensors of pure inorganic rare earth nanoparticles, the temperature ratio fluorescent probe based on triplet-triplet annihilation upconversion luminescence provided by the present invention is prepared into two groups of solid microcrystals with different temperature responsiveness of thermal activation and non-thermal activation systems, thereby avoiding confusion in energy transfer of photosensitizer and annihilation agent between the two groups of microcrystals, and achieving different doping ratios of the two upconversion microcrystals, both of which show a good linear correlation, which is easier to operate in practical applications than the prior art.

5. The temperature ratio fluorescent probe based on triplet-triplet annihilation upconversion luminescence provided by the present invention can visually see the color change of the material with temperature through the naked eye, thereby realizing the visualization of temperature sensing.

BRIEF DESCRIPTION OF THE DRAWINGS

The specific implementation modes of the present invention will be further described in detail below in conjunction with the accompanying drawings.

FIG. 1 shows a scanning electron microscope image of the thermally activated upconversion microcrystals prepared in Example 3.

FIG. 2 shows a scanning electron microscope image of the non-thermal activated upconversion microcrystals prepared in Example 3.

FIG3 shows a graph showing the relationship between the luminescence intensity of the thermally activated upconversion microcrystals prepared in Example 3 and the temperature, wherein (a) in FIG3 is a spectrum graph showing the luminescence intensity changing with temperature, and (b) is a graph showing the relationship between the maximum luminescence peak intensity and the temperature.

FIG4 shows a graph showing the relationship between the luminescence intensity of the non-thermally activated upconversion microcrystals prepared in Example 3 and temperature, wherein FIG4 (a) is a spectrum graph showing the luminescence intensity and temperature, and (b) is a graph showing the relationship between the maximum luminescence peak intensity and temperature.

FIG. 5 shows a graph showing the relationship between the luminescence intensity of the hybrid up-conversion microcrystals prepared in Example 3 and temperature.

FIG. 6 shows the ratio fluorescence graph of the hybrid up-conversion microcrystals prepared in Example 3.

FIG. 7 shows the luminescent colors of the hybrid up-conversion microcrystals prepared in Example 3 at 223K and 300K, respectively.

FIG8 shows the up-conversion luminescence spectra obtained from the experimental group and the control group in comparative experiment 1, wherein FIG8 (a) is the up-conversion luminescence spectrum of the experimental group, and FIG8 (b) is the up-conversion luminescence spectrum of the control group.

Detailed ways

In order to more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments and accompanying drawings. Similar components in the accompanying drawings are represented by the same reference numerals. It should be understood by those skilled in the art that the content specifically described below is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

Example 1

This embodiment provides a method for preparing a rare earth complex Yb(DBM) ₃ (H ₂ O), the structure of which is shown below.

0.672g (3.0eq) of dibenzoylmethane was dissolved in 70mL of acetone, and 9mL of potassium hydroxide (0.5M) aqueous solution was added. The mixture was heated to 60°C and refluxed for 30min. Then, 0.539g of neodymium chloride (1.0eq) dissolved in 15mL of water was added. The reaction was continued for 2h. After the reaction, a yellow solid precipitated. The solid was filtered to obtain a solid. The solid was recrystallized with acetone and cyclohexane to obtain Yb(DBM) ₃ (H ₂ O). The obtained crystals were identified by elemental analysis and FT-IR.

Elemental analysis calculated for C ₄₅ H ₃₅ YbO ₇ (%): C 62.79, H 4.10; found: C 62.81, H 4.06.

IR(ATR)＝3401(st, OH), 1605(st, C＝O), 809(st, Yb-O) cm ^-1 .

Example 2

This embodiment provides a multi-nuclear rare earth complex Yb ₅ (DBM) ₁₀ (OH) ₅ , the structure of which is shown below.

0.448 g (2.0 eq) of dibenzoyl ketone was dissolved in 38 mL of ethanol, 3 mL of sodium hydroxide (1 M) aqueous solution was added, the solution was heated to 75°C, and refluxed for 60 min. 0.438 g of neodymium nitrate (1.0 eq) dissolved in 9 mL of water was added, and the reaction was continued for 8 h. After the reaction, a yellow solid precipitated. The solid was filtered to obtain a solid, which was recrystallized from ethanol and tetrahydrofuran to obtain Yb ₅ (DBM) ₁₀ (OH) ₅ . The obtained crystals were identified by elemental analysis and FT-IR.

Elemental analysis calculated for C ₁₅₀ H ₁₁₅ Yb ₅ O ₂₅ (%): C 56.11, H 3.64; found: C 56.23, H 3.71.

IR(ATR)＝3443(st, OH), 1557(st, C＝O), 789(st, Yb-O) cm ^-1 .

Example 3

This embodiment provides a temperature ratio fluorescent probe based on triplet-triplet annihilation upconversion luminescence, and the preparation method thereof comprises the following steps:

Preparation of thermally activated upconversion microcrystals: In an air atmosphere, Yb(DBM) ₃ (H ₂ O) as the first photosensitizer and 9,10-(diphenylethynyl)anthracene (BPEA) as the first triplet annihilator were dispersed in 1 mL of tetrahydrofuran solution, wherein the concentration of Yb(DBM) ₃ (H ₂ O) was 0.0011 mmol/L, and the concentration of 9,10-(diphenylethynyl)anthracene was 0.03 mmol/L. When injected into water, solids would reprecipitate, stirred at 1000 r/min for 5 min, allowed to stand for 2 h, and centrifuged at 8000 r/min for 5 min. The precipitate was collected and dried in vacuum at 40°C to obtain thermally activated upconversion microcrystal powder. The microcrystalline structure was characterized by scanning electron microscopy. The result is shown in Figure 1, showing a 1-5 μm rod-like structure.

Preparation of non-thermally activated upconversion microcrystals: In an air atmosphere, Yb(DBM) ₃ (H ₂ O) as the second photosensitizer and N,N'-di(ethylpropyl)perylene-3,4,9,10-tetracarboxylic acid (PDI) as the second triplet annihilator were dispersed in 1 mL of tetrahydrofuran solution, wherein the concentration of Yb(DBM) ₃ (H ₂ O) was 0.004 mmol/L and the concentration of PDI was 0.04 mmol/L. When injected into water, solids would reprecipitate, stirred at 1000 r/min for 5 min, allowed to stand for 2 h, centrifuged at 8000 r/min for 5 min, the precipitate was collected, and vacuum dried at 20-40°C to obtain non-thermally activated upconversion microcrystal powder. The microcrystalline structure was characterized by scanning electron microscopy. The result is shown in Figure 2, showing a 5-10 μm leaf-like structure.

The two up-conversion microcrystalline powders were sieved out of large particles using a 100-mesh sieve, and the two sieved up-conversion microcrystalline powders were mixed in a mass ratio of 1:1, and oscillated in an oscillator for 5 minutes to obtain a uniform mixed up-conversion microcrystalline powder, namely, a temperature ratio fluorescent probe.

Upconversion variable temperature luminescence performance test of upconversion microcrystalline powder

In an oxygen-free environment, the thermally activated upconversion microcrystalline powder was placed at different temperatures to test the change in its upconversion luminescence intensity. The non-thermally activated upconversion microcrystalline powder was also tested in an oxygen-free environment at different temperatures for changes in its upconversion luminescence intensity. The excitation light wavelength used was 980nm. The results are shown in Figures 3 and 4.

As can be seen from Figures 3 and 4, the maximum luminescence peak position of the thermally activated upconversion microcrystalline powder is at 570nm, and the luminescence peak intensity gradually increases with increasing temperature, which belongs to the thermally activated upconversion system. The maximum luminescence peak position of the non-thermally activated upconversion microcrystalline powder is at 650nm, and the luminescence peak intensity gradually decreases with increasing temperature, which belongs to the non-thermally activated upconversion system. The mixing experiment of the two upconversion microcrystalline powders meets the basic conditions for ratio fluorescence.

Test on the upconversion variable temperature luminescence performance of mixed upconversion microcrystalline powder

In an oxygen-free environment, the mixed up-conversion microcrystalline powder, i.e., the temperature ratio fluorescent probe, was placed at different temperatures to test how its luminescence intensity changes with temperature. The excitation light wavelength used was 980nm. The results are shown in FIG5 .

As shown in Figure 5, the maximum luminescence peak wavelengths of the mixed up-conversion microcrystal powder are at 570nm and 650nm respectively, and the luminescence intensities are expressed as _I570 and _I650 respectively. _I570 / _I650 is expressed as the ratio of the luminescence intensities of the two. The relationship between I570/I650 _and temperature is shown in Figure 6. _I570 / _I650 increases linearly with increasing temperature. The fitting formula is _I570 / _I650 =0.01046T-1.9544, ^R2 =0.99351, where T is temperature in K. The curve shows that the ratio fluorescence based on the two-component TTA up _- conversion mixed microcrystals is dependent on temperature and can be used as a ratio fluorescence temperature sensor. After testing, its relative sensitivity is 2.8%/K at 223K.

Mixed upconversion microcrystalline powder upconversion temperature-dependent luminescence color change test

In an oxygen-free environment, the mixed up-conversion microcrystalline powder, i.e., the temperature ratio fluorescent probe, was placed at 223K and 300K respectively, with an excitation light wavelength of 980nm. The luminescent colors are shown in FIG7 . It is found that the luminescent color is yellow at 223K, and changes from yellow to orange at 300K, indicating that the mixed up-conversion microcrystalline powder has the function of indicating temperature through color changes, i.e., temperature changes can be visualized.

Example 4

This embodiment provides a temperature ratio fluorescent probe based on triplet-triplet annihilation upconversion luminescence. The preparation method is the same as that of Example 3, except that the mass ratio of thermally activated upconversion microcrystalline powder to non-thermally activated upconversion powder is changed to 1:10.

Upconversion variable temperature luminescence performance test of upconversion microcrystalline powder

The testing method is the same as that in Example 3. After testing, the maximum luminescence peak position of the thermally activated upconversion microcrystalline powder is 570nm, and its luminescence intensity gradually increases with increasing temperature, which belongs to the thermally activated upconversion system. The maximum emission peak position of the non-thermally activated upconversion microcrystalline powder is 650nm, and its luminescence intensity gradually decreases with increasing temperature, which belongs to the non-thermally activated upconversion system. The mixing experiment of the two upconversion microcrystalline powders meets the basic conditions as ratio fluorescence.

Test on the upconversion variable temperature luminescence performance of mixed upconversion microcrystalline powder

The testing method is the same as that in Example 3. After testing, the maximum luminescence peak wavelengths of the mixed up-conversion microcrystal powder are respectively at 570 nm and 650 nm, and the luminescence intensities are respectively expressed as I ₅₇₀ and I _650. I ₅₇₀ /I ₆₅₀ is expressed as the ratio of the intensities of the two. I ₅₇₀ /I ₆₅₀ increases linearly with increasing temperature. The fitting formula is I _570/650 =0.01968T-3.6885, R ² =0.99452, wherein T is the temperature in K. The curve shows that the ratio fluorescence based on the two-component TTA up-conversion mixed microcrystals is dependent on temperature and can be used as a ratio fluorescence temperature sensor. After testing, its relative sensitivity at 223 K is 2.8%/K.

Mixed upconversion microcrystalline powder upconversion temperature-dependent luminescence color change test

The test method is the same as that of Example 3. It is found that the luminescent color is yellow at 223K, and changes from yellow to orange at 300K, indicating that the mixed up-conversion microcrystalline powder has the function of indicating temperature by color change, that is, the temperature change can be visualized.

Example 5

This embodiment provides a temperature ratio fluorescent probe based on triplet-triplet annihilation upconversion luminescence. The preparation method is the same as that of Example 3, except that the first triplet annihilator is replaced with 9,10-bis[(triisopropylsilyl)ethynyl]anthracene, and the molar ratio of the first photosensitizer to the first triplet annihilator is changed to 1:1.

Upconversion microcrystalline powder upconversion variable temperature luminescence performance test

The testing method is the same as that in Example 3. After testing, the maximum luminescence peak position of the thermally activated upconversion microcrystalline powder is 520nm, and its luminescence intensity gradually increases with increasing temperature, which belongs to the thermally activated upconversion system. The maximum emission peak position of the non-thermally activated upconversion microcrystalline powder is 650nm, and its luminescence intensity gradually decreases with increasing temperature, which belongs to the non-thermally activated upconversion system. The mixing experiment of the two upconversion microcrystalline powders meets the basic conditions as ratio fluorescence.

Test on the upconversion variable temperature luminescence performance of mixed upconversion microcrystalline powder

The testing method is the same as that in Example 3. After testing, the maximum luminescence peak wavelengths of the mixed up-conversion microcrystal powder are respectively at 520 nm and 650 nm, and the luminescence intensities are respectively expressed as I ₅₂₀ and I _650. I ₅₂₀ /I ₆₅₀ is expressed as the ratio of the intensities of the two. I ₅₂₀ /I ₆₅₀ increases linearly with increasing temperature. The fitting formula is I _520/650 =0.02400T-4.0926, R ² =0.99431, where T is temperature in K. The curve shows that the ratio fluorescence based on the two-component TTA up-conversion mixed microcrystals is dependent on temperature and can be used as a ratio fluorescence temperature sensor. After testing, its relative sensitivity at 223 K is 1.9%/K.

Mixed upconversion microcrystalline powder upconversion temperature-dependent luminescence color change test

The test method is the same as that of Example 3. It is found that the luminescent color is green at 223K, and the luminescent color changes from green to orange at 300K, indicating that the mixed up-conversion microcrystalline powder has the function of indicating temperature by color change, that is, the temperature change can be visualized.

Example 6

This embodiment provides a temperature ratio fluorescent probe based on triplet-triplet annihilation upconversion luminescence. The preparation method is the same as that of Example 3, except that the second triplet annihilator is changed to N,N'-di-n-octyl-3,4,9,10-perylenetetracarboxamide diimide (ODI), and the molar ratio of the first photosensitizer to the first triplet annihilator is changed to 1:40.

Upconversion variable temperature luminescence performance test of upconversion microcrystalline powder

The testing method is the same as that in Example 3. After testing, the maximum luminescence peak position of the thermally activated upconversion microcrystalline powder is 570nm, and its luminescence intensity gradually increases with increasing temperature, which belongs to the thermally activated upconversion system. The maximum emission peak position of the non-thermally activated upconversion microcrystalline powder is 600nm, and its luminescence intensity gradually decreases with increasing temperature, which belongs to the non-thermally activated upconversion system. The mixing experiment of the two upconversion microcrystalline powders meets the basic conditions as ratio fluorescence.

Test on the upconversion variable temperature luminescence performance of mixed upconversion microcrystalline powder

The testing method is the same as that in Example 3. After testing, the maximum luminescence peak wavelengths of the mixed up-conversion microcrystal powder are respectively at 570 nm and 600 nm, and the luminescence intensities are respectively expressed as I ₅₇₀ and I _600. I ₅₇₀ /I ₆₀₀ is expressed as the ratio of the intensities of the two. I ₅₇₀ /I ₆₀₀ increases linearly with increasing temperature. The fitting formula is I _570/600 =0.40968T-75.549, R ² =0.98322, wherein T is temperature in K. The curve shows that the ratio fluorescence based on the two-component TTA up-conversion mixed microcrystals is dependent on temperature and can be used as a ratio fluorescence temperature sensor. After testing, its relative sensitivity at 223 K is 2.6%/K.

Mixed upconversion microcrystalline powder upconversion temperature-dependent luminescence color change test

The test method is the same as that of Example 3. It is found that the luminescent color is yellow at 223K, and changes from yellow to orange at 300K, indicating that the mixed up-conversion microcrystalline powder has the function of indicating temperature by color change, that is, the temperature change can be visualized.

Example 7

This embodiment provides a temperature ratio fluorescent probe based on triplet-triplet annihilation upconversion luminescence. The preparation method is the same as that of Example 5, except that the second triplet annihilator is changed to N,N'-di-n-octyl-3,4,9,10-perylenetetracarboxylic acid diimide (ODI).

Upconversion microcrystalline powder upconversion variable temperature luminescence performance test

The testing method is the same as that in Example 3. After testing, the maximum luminescence peak position of the thermally activated upconversion microcrystalline powder is 520nm, and its luminescence intensity gradually increases with increasing temperature, which belongs to the thermally activated upconversion system. The maximum emission peak position of the non-thermally activated upconversion microcrystalline powder is 600nm, and its luminescence intensity gradually decreases with increasing temperature, which belongs to the non-thermally activated upconversion system. The mixing experiment of the two upconversion microcrystalline powders meets the basic conditions as ratio fluorescence.

Test on the upconversion variable temperature luminescence performance of mixed upconversion microcrystalline powder

The testing method is the same as that in Example 3. After testing, the maximum luminescence peak wavelengths of the mixed up-conversion microcrystal powder are respectively at 520 nm and 600 nm, and the luminescence intensities are respectively expressed as I ₅₂₀ and I _600. I ₅₂₀ /I ₆₀₀ is expressed as the ratio of the intensities of the two. I ₅₂₀ /I ₆₀₀ increases linearly with increasing temperature. The fitting formula is I _520/600 =0.1012T-19.7344, R ² =0.99621, where T is temperature in K. The curve shows that the ratio fluorescence based on the two-component TTA up-conversion mixed microcrystals is dependent on temperature and can be used as a ratio fluorescence temperature sensor. After testing, its relative sensitivity at 223 K is 3.6%/K.

Mixed upconversion microcrystalline powder upconversion temperature-dependent luminescence color change test

The test method is the same as that of Example 3. It is found that the luminescent color is green at 223K, and the luminescent color changes from green to orange at 300K, indicating that the mixed up-conversion microcrystalline powder has the function of indicating temperature by color change, that is, the temperature change can be visualized.

Example 8

This embodiment provides a temperature ratio fluorescent probe based on triplet-triplet annihilation. The preparation method is the same as that of Example 5, except that the second triplet annihilator is changed to rubrene, the molar ratio of the first photosensitizer and the first triplet annihilator is changed to 1:5, and the molar ratio of the second photosensitizer and the second triplet annihilator is changed to 1:35.

Upconversion microcrystalline powder upconversion variable temperature luminescence performance test

The testing method is the same as that in Example 3. After testing, the maximum luminescence peak position of the thermally activated upconversion microcrystalline powder is 520nm, and its luminescence intensity gradually increases with increasing temperature, which belongs to the thermally activated upconversion system. The maximum emission peak position of the non-thermally activated upconversion microcrystalline powder is 580nm, and its luminescence intensity gradually decreases with increasing temperature, which belongs to the non-thermally activated upconversion system. The mixing experiment of the two upconversion microcrystalline powders meets the basic conditions for ratio fluorescence.

Test on the upconversion variable temperature luminescence performance of mixed upconversion microcrystalline powder

The testing method is the same as that in Example 3. After testing, the maximum luminescence peak wavelengths of the mixed up-conversion microcrystal powder are 520 nm and 580 nm, respectively. The luminescence intensities are expressed as I ₅₂₀ and I ₅₈₀ , respectively. I ₅₂₀ /I ₅₈₀ is expressed as the ratio of the intensities of the two. I ₅₂₀ /I ₅₈₀ increases linearly with increasing temperature. The fitting formula is I _520/580 =1.1227T-225.588, R ² =0.99368, where T is temperature in K. The curve shows that the ratio fluorescence based on the two-component TTA up-conversion mixed microcrystals is dependent on temperature and can be used as a ratio fluorescence temperature sensor. After testing, its relative sensitivity at 223 K is 4.5%/K.

Mixed upconversion microcrystalline powder upconversion temperature-dependent luminescence color change test

The test method is the same as that of Example 3. It is found that the luminescent color is green at 223K and changes from green to yellow at 300K, indicating that the mixed up-conversion microcrystalline powder has the function of indicating temperature by color change, that is, the temperature change can be visualized.

Example 9

This embodiment provides a temperature ratio fluorescent probe based on triplet-triplet annihilation upconversion luminescence. The preparation method is the same as that of Example 3, except that the first photosensitizer is changed to _Yb5 (DBM) ₁₀ (OH) ₅ , the molar ratio of the first photosensitizer to the first triplet annihilation agent is changed to 1:1, and the molar ratio of the second photosensitizer to the second triplet annihilation agent is changed to 1:4.

Upconversion variable temperature luminescence performance test of upconversion microcrystalline powder

The testing method is the same as that in Example 3. After testing, the maximum luminescence peak position of the thermally activated upconversion microcrystalline powder is 570nm, and its luminescence intensity gradually increases with increasing temperature, which belongs to the thermally activated upconversion system. The maximum emission peak position of the non-thermally activated upconversion microcrystalline powder is 650nm, and its luminescence intensity gradually decreases with increasing temperature, which belongs to the non-thermally activated upconversion system. The mixing experiment of the two upconversion microcrystalline powders meets the basic conditions as ratio fluorescence.

Test on the upconversion variable temperature luminescence performance of mixed upconversion microcrystalline powder

The testing method is the same as that in Example 3. After testing, the maximum luminescence peak wavelengths of the mixed up-conversion microcrystal powder are respectively at 570 nm and 650 nm, and the luminescence intensities are respectively expressed as I ₅₇₀ and I _650. I ₅₇₀ /I ₆₅₀ is expressed as the ratio of the intensities of the two. I ₅₇₀ /I ₆₅₀ increases linearly with increasing temperature. The fitting formula is I _570/650 =0.01134T-2.1712, R ² =0.99921, wherein T is the temperature in K. The curve shows that the ratio fluorescence based on the two-component TTA up-conversion mixed microcrystals is dependent on temperature and can be used as a ratio fluorescence temperature sensor. After testing, its relative sensitivity at 223 K is 3.2%/K.

Mixed upconversion microcrystalline powder upconversion temperature-dependent luminescence color change test

The test method is the same as that of Example 3. It is found that the luminescent color is yellow at 223K, and changes from yellow to orange at 300K, indicating that the mixed up-conversion microcrystalline powder has the function of indicating temperature by color change, that is, the temperature change can be visualized.

Example 10

The present embodiment provides a temperature ratio fluorescent probe based on triplet-triplet annihilation upconversion luminescence. The preparation method thereof is the same as that of Example 3, except that the first photosensitizer is changed to palladium (II) tetraphenyltetrabenzoporphyrin, the first triplet annihilation agent is changed to 9,10-diphenylanthracene, the second photosensitizer is changed to palladium (II) tetraphenyltetrabenzoporphyrin, the second triplet annihilation agent is changed to rubrene, the molar ratio of the first photosensitizer to the first triplet annihilation agent is changed to 1:100, the molar ratio of the second photosensitizer to the second triplet annihilation agent is changed to 1:200, and the wavelength of the excitation light used is changed to 635 nm.

Upconversion variable temperature luminescence performance test of upconversion microcrystalline powder

The testing method is the same as that in Example 3, the only difference is that the wavelength of the excitation light used is 635 nm. After testing, the maximum luminescence peak position of the thermally activated upconversion microcrystalline powder is 470 nm, and its luminescence intensity gradually increases with increasing temperature, which belongs to the thermally activated upconversion system. The maximum emission peak position of the non-thermally activated upconversion microcrystalline powder is 580 nm, and its luminescence intensity gradually decreases with increasing temperature, which belongs to the non-thermally activated upconversion system. The mixing experiment of the two upconversion microcrystalline powders meets the basic conditions as ratio fluorescence.

Test on the upconversion variable temperature luminescence performance of mixed upconversion microcrystalline powder

The test method is the same as that of Example 3, except that the wavelength of the excitation light used is 635 nm. After testing, the maximum luminescence peak wavelengths of the mixed up-conversion microcrystal powder are respectively 470 nm and 580 nm, and the luminescence intensities are respectively expressed as I ₄₇₀ and I ₅₈₀ . I ₄₇₀ /I ₅₈₀ is expressed as the ratio of the intensities of the two. I ₄₇₀ /I ₅₈₀ increases linearly with increasing temperature. The fitting formula is I _470/580 =0.02482T-4.4169, R ² =0.99945, where T is the temperature in K. The curve shows that the ratio fluorescence based on the two-component TTA up-conversion mixed microcrystals is dependent on temperature and can be used as a ratio fluorescence temperature sensor. After testing, its relative sensitivity at 223 K is 2.2%/K.

Mixed upconversion microcrystalline powder upconversion temperature-dependent luminescence color change test

The test method is the same as that in Example 3, except that the wavelength of the excitation light used is 635 nm. It is found that the luminescent color is blue at 223 K, and the luminescent color changes from blue to yellow at 300 K, indicating that the mixed up-conversion microcrystalline powder has the function of indicating temperature by color change, i.e., the temperature change can be visualized.

Embodiment 11

This embodiment provides a test application of a temperature ratio fluorescent probe in an aqueous system environment. The preparation method of the temperature ratio fluorescent probe is the same as that of Example 3, and then 5 mg of mixed up-conversion microcrystals are dispersed in 5 mL of an aqueous solution containing sodium dodecyl sulfate (SDS) for subsequent testing, wherein the SDS concentration is 10 g/L.

Upconversion variable temperature luminescence performance test of upconversion microcrystalline powder

The testing method is the same as that in Example 3, except that the testing temperature range is 273K-300K. After testing, the maximum luminescence peak position of the thermally activated upconversion microcrystalline powder is 570nm, and its luminescence intensity gradually increases with increasing temperature, belonging to a thermally activated upconversion system. The maximum emission peak position of the non-thermally activated upconversion microcrystalline powder is 650nm, and its luminescence intensity gradually decreases with increasing temperature, belonging to a non-thermally activated upconversion system. The mixing experiment of the two upconversion microcrystalline powders meets the basic conditions as ratio fluorescence.

Test on the upconversion variable temperature luminescence performance of mixed upconversion microcrystalline powder

The test method is the same as that in Example 3, except that the test temperature range is 273K-300K. The maximum luminescence peak wavelengths of the mixed up-conversion microcrystalline powder aqueous solution are tested at 570nm and 650nm, respectively, and the luminescence intensities are expressed as _I570 and _I650 , respectively. _I570 / _I650 is expressed as the ratio of the intensities of the two. I570/ _I650 increases linearly with increasing temperature. The fitting formula is _{I570 /650} = 0.01055T-1.6784, ^R2 = 0.98521, where T is temperature in K. The curve shows that the ratio fluorescence of the two-component TTA up-conversion mixed microcrystalline aqueous solution is dependent on temperature and can be used as a ratio fluorescence temperature sensor. The relative sensitivity at 273K is tested to be 1.5%/K.

Mixed upconversion microcrystalline powder upconversion temperature-dependent luminescence color change test

The testing method is the same as that in Example 3, except that the testing temperature range is 273K-300K. It is found that the luminescent color is yellow at 273K, and changes from yellow to orange at 300K, indicating that the mixed up-conversion microcrystalline aqueous solution has the function of indicating temperature by color change, i.e., the temperature change can be visualized.

Comparative experiment 1

In order to further study the effect of the preparation method of mixed up-conversion microcrystalline powder on ratio fluorescence, this comparative experiment provides an experimental group and a control group, and analyzes and compares their luminescence properties:

The preparation method of the temperature ratio fluorescent probe of the experimental group is exactly the same as that of Example 3.

The preparation process of the control group is as follows:

1) Preparation of a thermally activated upconversion system: Yb(DBM) ₃ (H ₂ O) was used as the first photosensitizer, BPEA was used as the first triplet annihilation agent, and toluene was used as the solvent to disperse the first photosensitizer and the first triplet annihilation agent, wherein the concentration of the first photosensitizer was 0.0011 mmol/L, and the concentration of the first triplet annihilation agent was 0.03 mmol/L, to prepare a thermally activated upconversion system in a solution state;

2) Preparation of non-thermal activation upconversion system: Yb(DBM) ₃ (H ₂ O) was used as the second photosensitizer, PDI was used as the second triplet annihilation agent, and toluene was used as the solvent to disperse the second photosensitizer and the second triplet annihilation agent, wherein the concentration of the second photosensitizer was 0.004 mmol/L, and the concentration of the second triplet annihilation agent was 0.04 mmol/L, to prepare a non-thermal activation upconversion system in a solution state;

3) The two upconversion systems were mixed and deoxygenated by bubbling with argon for 1 hour.

The research results are shown in Figure 8. Under the same 980nm excitation light source pumping, the up-conversion luminescence of the control group is a single luminescence peak, while the experimental group has two luminescence peaks. This shows that the preparation method provided by the present invention avoids too many system components and chaotic energy transfer (such as the energy of the first photosensitizer is transferred to the second triplet annihilator). At the same time, the two luminescence peaks can be used for ratio fluorescence temperature sensing.

Comparative experiment 2

In order to study the effect of ratio fluorescence of two upconversion materials with different luminescent colors on the visualized temperature response, this comparative experiment provides an experimental group, a control group 1 and a control group 2, and analyzes and compares their luminescent properties:

The preparation method of the temperature ratio fluorescent probe of the experimental group is exactly the same as that of Example 3.

Control group 1: only the thermally activated upconversion microcrystals in Example 3 were used, and a single upconversion system was used as a ratiometric fluorescent probe to test how the luminescent color changes with temperature.

Control group 2: Only the non-thermally activated upconversion microcrystals in Example 3 were used, and a single upconversion system was used as a ratiometric fluorescent probe to test how the luminescent color changes with temperature.

The research results are shown in Table 1. Under the same 980nm excitation light source pumping, the control group 1 and the control group 2 will not change color when the ambient temperature changes from 223K to 300K, and only when the two upconversion microcrystals appear at the same time in the experimental group will there be a visual change.

Table 1

Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims (10)

1. A temperature ratio fluorescent probe based on triplet-triplet annihilation upconversion luminescence, characterized in that the temperature ratio fluorescent probe comprises thermally activated upconversion microcrystals and non-thermally activated upconversion microcrystals; the thermally activated upconversion microcrystals comprise a first photosensitizer and a first triplet annihilation agent, and the non-thermally activated upconversion microcrystals comprise a second photosensitizer and a second triplet annihilation agent; Wherein, the first photosensitizer and the second photosensitizer have the same excitation wavelength and are selected from metal complexes absorbing in the near-infrared region of 600-1000nm. 2. The temperature ratio fluorescent probe according to claim 1, characterized in that the first photosensitizer and the second photosensitizer are selected from any one of a tetraphenyltetrabenzoporphyrin metal complex of palladium or platinum, a rare earth complex with a photosensitive core of ytterbium, a rare earth complex with a photosensitive core of neodymium, and a rare earth complex with a photosensitive core of thulium; The first triplet annihilator is selected from one or more of 9,10-diphenylanthracene or its derivatives, 9,10-(diphenylethynyl)anthracene or its derivatives, and 9,10-bis[(triisopropylsilyl)ethynyl]anthracene; The second triplet annihilator is selected from one or more of rubrene, perylenetetracarboxylic acid diimide or their derivatives. 3 . The temperature ratio fluorescent probe according to claim 1 , wherein the first photosensitizer and the second photosensitizer are selected from diketone complexes whose photosensitive core is ytterbium or palladium (II) tetraphenyltetrabenzoporphyrin. 4 . The temperature ratio fluorescent probe according to claim 1 , wherein the molar ratio of the first photosensitizer to the first triplet annihilator is 1:1-1:500; and the molar ratio of the second photosensitizer to the second triplet annihilator is 1:1-1:300. 5 . The temperature ratio fluorescent probe according to claim 1 , wherein the mass ratio of the thermally activated upconversion microcrystals to the non-thermally activated upconversion microcrystals is 1:1-1:1000. 6 . The temperature ratio fluorescent probe according to claim 1 , wherein the mass ratio of the thermally activated upconversion microcrystals to the non-thermally activated upconversion microcrystals is 1:1-1:50. 7. The method for preparing the temperature ratio fluorescent probe according to any one of claims 1 to 6, characterized in that it comprises the following steps: Dispersing the first photosensitizer and the first triplet annihilator in an organic solvent, then adding them into water, stirring until the mixture is uniform, standing, centrifuging, and drying to obtain thermally activated upconversion microcrystals; The second photosensitizer and the second triplet annihilator are dispersed in an organic solvent, then added into water, stirred until the mixture is uniform, allowed to stand, centrifuged, and dried to obtain non-thermally activated upconversion microcrystals; The thermally activated upconversion microcrystals and the non-thermally activated upconversion microcrystals are fully mixed in proportion to obtain a temperature ratio fluorescent probe. 8. The preparation method according to claim 7, characterized in that the organic solvent is selected from one or more of tetrahydrofuran, chloroform, dimethyl sulfoxide, and N,N-dimethylformamide. 9. Use of the temperature ratio fluorescent probe according to any one of claims 1 to 6 in the field of temperature sensing. 10 . The use according to claim 9 , characterized in that the temperature ratio fluorescent probe is used in visual non-contact temperature monitoring inside a material or device.